Liquid fuel burner



6. [J1 STADLER 1,857.667

LIQUID FUEL BURNER May 10, 1932.

Filed June 13, 1928 129129225302.- George :1 6 21102293" Patented May 16, 1932 UMTED STATE-SPA? GEORGE J. STADLER, or BOSTON, anassAonusncwrsgassreneia TO ndaman. BALlLARD mconronnrnn, or'sos'ron, MAssAo sE'r'rsncoaronn'rlon on nrnssncnusnrrs tastes? LIQUID runnnunnna Application filed June 13,

This invention relates to liquid fuelburners in which atomized oil or other liquid fuel is delivered to the combustion chamber of the heater, and has for its Object the reduction to a minimum of the noise due to combustion which ordinarily accompanies the operation of such a burner and'the increase in the efficiency of combustion. 1

In the operation of burners of this type, the most effective method of delivering the liquid fuel to the combustion chamber, particularly where the heavier fuel oils are employed,has been found to be through the use ofan atom- .izing device from which the liquid fuel in-a lng under a high velocity 1n1a condensed and well atomized condition isfdeliv'ered to, the combustion chamber-in the form of a'diverg ing spray under a substantial initial velocity, relatively compact or, condensed at and near the delivery device. Such delivery'device, for example, is frequently in the form of an orificed nozzle through, which the atomized fuel is discharged under substantial pressure, 7 thereby "producing a jet, which at andadja cent the nozzle is relatively compact, the most efficient form of jet or spray being one in which the liquid fuel is sub-divided into a large number of minute particles moving at a relatively high velocity on emergence from the nozzle or other delivery device. The supply of air-necessary to effect and support comb-ustion is ordinarily admitted at or about the delivery device, as, for example, at 'or about the mouth of the nozzle, and about the compacted portion of the jet or spray, the i main air supply being thereby brought initially into contact with the atomized fuel where it is in its highly compacted and condensed state. This results ina noise of. a roaring or reverberatory nature produoedbythe combustion of the fuel which" is apart from any mechanical noise incidental to the operation of the pump, motor or other moving parts to supply thejet, and this noise, in spite of attempts to mufiie or deaden it, is in many cases objectionable and detrimental. This methodof air admission, moreover, re-' sults in more or less incomplete combustion of the fuel due to insufiicient commingling of the air supply with the atomized'particles of fuel, since a certain proportion of the 1928. Serial Noiasaoas.

atomized particles. moving a j relatively high velocity within the compacted-portion .of the j et or spray tend to'be carried through and out of range ofthe air Without intimate contact therewith and,*impingingon the walls or floor of the combustion chamber, tend to carbonize and form a depositthereon,

The reverberatory roa'r or noise referred to appears to be due inlarg'e measure to the fact that the combustion which takes place be-:

tween the small individual particles of liquid in large measure near the delivery end ofthe et or spraywhere the fuel particles are movcompacted state andin a relatively-small, -refuel and theauxiliary airsupp'ly is initiated stricted space. -The gases resultingffrom such combustion being thus more or-less confined in or about this compacted or condensed.

region, their sudden expansion following combustion results m an infinite number-of small explosions producing in the aggregate the reverberat'ory'roar referred to.

I have found thatby causing the main air supply to 'initiallyengage and -'commingle 'with the atomized fuel relatively remote from the deliverydevicaand' in the expand; ed part of the jet or spray Where the latter "has had opportunity to become enlarged and spread over a substantial area and 'where liquid particles "are themselves Widely diffused, the commin'g'ling'is spread over a Wide area and the combustion is initiated and takes place throughout a large portion of thecombustion chamber space." The gaseous products of combustion between the individ- 1 ual fuel particles and the auxiliary supply being thereby" relatively unconfined, their explosive characteris substantially eliminat-v ed and the'acooinpanying noise reduced to a minimum. Instead of there being'a central, well d'efined jet or spray of flame impinging "against thewalls of the combustion chamber accompanied by the roar referred to, theap pearance-is more nearlytha't vof a solid mass of fiamey spread uniformly throughout the combustion space, burning "quietly and evenly. V

The ideztldondition is reached-Where each particle of atomized fuel, while stillin' mo- 1 tion and before contact with the walls of the combustion chamber, becomes surrounded by preferably preheated air, this resulting in a substantially complete and perfect combustion of the atomized fuelwithout carbonizing deposits and with thesubstantial elin1ination of all :noise. This condition, "Ihave found, is closely approximated by preheating the air supply and so directing -it into the combustion chamber as'tocause its wide dilli'usion throughoutand' to cause it initially to impinge on the jet or spray of atomized liquid fuel after the latter has itslf'become;

diffused and spread, but ,preferably while still traveling from thenozzle and prior to 4 impinging against the walls ;of the :comhus- V ition :chamber.

,nozzle and air supplyzdevices to the combustion;chamberrofa heater;

Eig. 21s,: a central,,- sectional=- elevation taken through \the (combustion chamber -of :the heater .onaslightly enlarged. scale; Fig. 3iis-za plan view :of theiheater with the .zflooring-iof the combustion-chamber :re-

, moved; :and

Fig. 4 is an :end eleva't-ion-efthe nozzle showing -;the 3' et 1 forming 'aorifice.

{Referring to the' drawings land to ;the disclosed embodiment of "the invention, :there is shownfor illustrative purposes-a liquid ifuel burner comprising-a burner :nozzle 11 pm yided with 'a jet 'formirrgsorifice '13 (.-Fi'g. 4l) which ;.is preferably inqthe -:form of. an elongated, {horizontals-lot, so that, viewed in elevation (;-F;ig. 2-),1the jet zformed thereby as- ?sumes arelatively flattened-shape-zbut;viewed in plan QFig. 11), is relatively .-:fiared.' Accordingly,"=while compact and condensed at the nozzle, the jetspreadslateral lyas it .is projected through the-:cha-mber, ,as is ind-i- -cated in. Figs. -.1 and 2. The invention, zho w- 11cver,;in-its broader aspects is not limited-to a jet;or spray of any; specificform.

EFor the punpose of illustration, the fuel supplied-by thebuzrner is herein assumed to be oil,;-although other liquidefuels maybe employed 7 lAtom-ized oi l is supplied to the nozzle by suitable. means, as, for example, through v(the delivery pipe ;15,by .a =rotary pump- (not shown) driven by zthemotor l7 and-adapted to force a supply of 'commingledair and-oil from the intermediate supply chamber 19 which draws its supply of fuel froma main reservoir ortank through the suction pipe 21.-

WVhile the specific construction of the. means reams? adopted for supplying and forcing atomized fuel through the burner nozzle is unimportant, 1 have herein represented, without detailed illustration, as a typical example of such devices, the fuel feeding apparatus disclosed in vthe prior patent to Goodridge No. 1,631,859,.

Referring to the theater with which the burner is associated, there is illustrated a combustion chamber 23 comprising apart :of the-heater'25 and having a wall l1ning27and floor 29 of refractory material. The heater may be of the hot water, steam or other type and may beof any desired shape or size,

although an ordinary upright, round heater is-herein shown .for thepurpose of illustration. I 7

'Thenozzle L1 jprotrudes into the-space of r the combustion chamber through the casing 131 whichcarries the sparking electrodes 33 for the ignition -of;the,fuel, and with :the

.Premainder of the .combustioh chamber, is

preferably closed against the ,admission of any substantial supply gofaincrceptas hereinafter described.

:To provide theg'mainsupply of air for supporting the combustion-of the .oil, an -air admission opening35 is provided at the front o f ;the heaterbelow the nozzlel1 and between :thechamber floor 29 and the base on which the-theater rests. lllhe air admission opening 7 m ay be regulated by means of .a damper -;The air admission opening 35 communicates withanair supply passage 39 extending from therfront of the heater toward the rear thereof, the passage-being gpart'itiioned ofi by ,bricking 41 from the. space at either side thereof-beneath the combustion chamber, so

-- -thatthe :ai-ris compelled to travel from the .front toward the rear, and in its 1 travel, during thfeoperatlon of the burner, is preheated by contact withthe heated flooring.

At its reareend the passage 39 ropensxlaterally in two branches 4L3 arranged to V conductv the air back again toward the front of :the comybLl-SlllOll chamber at opposite sides of the vpassage 39. v v v To deliver the air to'the combustion chamberathere a re'located in advance ofthe nozzle 1'1 beneath "the fiared' or exp ended portion-of :the jet, and herein substantially m-idwaythe length a'off the combustion chamber, a series ofairydelivery openings arranged in the "floor 29, these being herein shown in the form of transverse slots, three in number, the middle one45 of which extends across the width-of the air passage 39'to receive air therefrom, While the remaining two slots 47 r are positioned in substantialal-ignment with,

"but'at oppositesides of, the slot 45 and communicate with the passages 43. The slots 47 have free, communication with' and extend c laterally from the passages 43am are of greater width than the central slot 45, herein extending approximately of the combustion chamber. v Theair entering through the admission to the sidewalls opening 35, under the draftinduced by the heater flue, flows through the passage 39 to the slot 45' wherea portion is directed up wardly through the floor of the combustion chamber. The remainder of the air supply divides itself into two parts, returning through the branches 4:3 to the slots47 where 7 so that the entire air supply entering the passage 35 is confined to the paths presented by the passages 39 and 43 and, after being preheated by passing in contact with the heated walls of the combustion chamber,

is caused to be delivered through the floor slots.

The air supply, which is thus preheated and Widely diffused across the combustion chamber on its entrance thereinto, is directed upwardly and impinges against the liquid oil'while still traveling as a part of the jet" and before the liquid particles have themselves impinged against the rear walls of the combustion chamber so that deposits of unconsumed fuel on the side walls or floor are prevented. This contact between the air and atomized oil, however, is had initiallyin the expanded or flared. part of the jet, so that the combustion is spread over a wide area of the combustion chamber and the gases of combustion are formed and allowed to expand in a relatively unconfined space. The fact that the contact between the upwardly moving air and the somewhat flared and flattened jet takes place where the liquid particles have lost increase the spread and diffusion of the commingled air and liquid oil particles'over a still greater portion of the space of the chamber while the fuel is undergoing combustion. Preferably the jet or spray for its, full expandedarea is met or overlapped by the'air supply so that all of the atomized particles of oil contained withinthejet or spray are obliged to impinge against the incoming air.

In the operation of the burner there is a slight tendency for some individual particles of oil to gravitate down from thejet and to reach the floor of the chamber between the nozzle and the air admission opening 45 and there carbonize and form. an objectionable deposit. To insure the combustion of such particlesas tend to gravitate from the jet, there is provided an auxiliary air supply which is admitted through a small slot 49 also communicating with the air-passage 39 on can be delivered to the chamber. 1 w a large portion of their velocity also helps to but located a short distance from th-e'slot45, between the latter and the nozzle 11.?The small, limited air supply entering theslot 49 tends to be drawn toward the front of the combustion chamber, just abovethe floor 7 thereof, by the suction induced through. the

jet, where it encounters the gravitating .particles of oiland commingles with the latter to initiate and j promote" the combustion thereof. n 1: 15 The admission of air through the described arrangement not only reduces to a negligible amount the noise of combustion, which has heretofore characterized burners of this class, but also producesa more perfect and-corn a the front or nozzle end of the combustion h g chamber as well as toward the sides and the back. This is .of particular advantage i'n the case of boilers of thesectiona'lIor elongated type where oilrburners have heretofore resulted in concentratingthe'flame.at the rear ,2 l of the combustion spac'e.--Throughthe'emf j ployment of the present invention'all sections of the boiler, b-othfront as well as rear, may be heated with substantial uniformity; V

In connection with the described methodof g supplying air to the combustion chamber,

there is provided meanswhich tends to cutoff or reduce the air supply when the burner ceases operation, acting however tov restore h such supply as soon as it 'is required byrthe ,19 starting up of the burner through the action of a house thermostat and insuring such air supply to thec'ombustion chamber beforeany I Herein for this purpose the damper 37 is connected to a bell crank lever arm61-having a link connection-'63 to the leverarm 65 which is actuated by the solenoid magnet 67, V the windings of which are incircuit with the motor17; :When the motor isdeenergized the magnetwill also be, deenergized and the damper 37 drops gravity to its closed'position, thereby cutting off; the air supply which would otherwise be drawn through the com 'bustionrh'amber under the natural draftof 1 the chimney and tend to=.c0ol down more rapidly the heatingmediumcontained within the heater. As soonas the house thermostat acts, howeve'r,-to start up the burner, the magnet 1s "energizedand this serves to lift -,;1

the damper to its open position, initiating the full air supply in advance of the time that any oil can bedelive'i'ed through the nozzle. The fact that the damper, controlling devi'ce acts to openjthedamper simultaneously with 5139 L the-energization of the motor renders itlim possible for: any oil to be delivered by the pump to the nozzle until after the air sup- 7 'plfyhasbeen. first provided; I has While I have herein shown and described for the purpose of illustration one/specific embodiment of'the invention and one method ofcarrying it into eilect, it is to be under-- stood that extensive "deviations may be made from the described form and arrangement of parts, and that the PIlIlClPlGS'O'I the mvention may be broadlyapplied to a wide variety of heaters requiring the admission of air to the combustion chamber under w1d.c

1y varying conditions and through widely varying means, all without departing from the spirit thereof.

What I claim is v a 1. In a liquid fuel furnace, the combination with a heater: having a combustion chamber provided with a floor, of a burner nozzle having a jet forming orifice, means for forcing a mixture of atomized liquid fuel under pressurethrough' the orificeto form a jet within the combustion chamber over the floor, and 7 an air admission passage formed beneath the ,floor forpreheating the air, said passage having an air inlet at one side of the heater and extending; thence across the heater beneath the floor and providednear the mid por-" tion of the chamber with an air delivery opening. through the floor and in line with fthe' jet, said passage extending thence to q the opposite side of the heater and thence revers'ely to an air delivery openingglaterally positioned out of line with the ct and relatively remote from the nozzle and adapted to deliver air to the flared portion of the jet.

2. In a liquid fuel furnace, the combination with a heater having a combustion chamber provided with a floor, of a burner nozzle havinga" jet forming orifice, means for forcing a IIIIXtUIBVOI atomized hquld fuel under pressure through the orifice to *form a jet within the combustion chamber over the floor, air delivery openings in the floor relatively remote from the-nozzle, including an openingaligned with-the jet and lateral openings at opposite sides thereof adapted to deliver air'to the flared portion of the jet, and an air inlet passage extending beneath the floor from" one side of the heater tosaid ranged to deliver air to the flared portion of the jet relatively remoteufromthe. nozzle,:a

second air opening: aligned with theajet rela tively nearer the nozzle, and an airinl'e't passage extending'beneath the fioor'from one side of the heater and communicating first with saidaligned air delivery opening, thence extending to. the opposite side of the heater, and ,thence reversely through separated branches'to said lateral air delivery openings.

In testimony whereof, I- have signed my name to'this specification.

GEORGE J. STADLEIRJ:

eluding; laterally positioned openings ar- 

